Circuit interrupter



Dec. 19, 1950 1.. LUDWIG ET AL CIRCUIT INTERRUPTER 2 Sheets-Sheet l Filed April 30, 1945 n m w a .6 i 5.

' INVENTORS dear) I? luaw' jg and en 2.7071 PBarer: BY

% fown WITNESSES: W iii Patented Dec. 19, 1950 STAT PATENT F F ICE CIRCUIT INTERRU-PIER Leon R. Ludwig; Wilkinsbarg, a-nd'Benjam-in P.

Baker, Turtleflreek, Ia., assi-gnnrs to wes'fiingfhause: Electric Corporation;

East Pittsburgh,

:Pa a-zcorparation of Pennsylvania Application April 30, 1945., JSeriaiNo. 5,911,047

\3;1Claims:.,, '(Cl. Mll -15D) ver-itien .to' adapt such an improved mountingarrangement-to a circuit 'interrupt'eroi' the liquid break type, preferably using an oil pool construction;

We prepose to--;oerrr-1i't the'entire breaker sbructare tt-e be redesigned meme-substantially one-half of tl'ie parts used type ei breaker, i; =one' interrupter, one isolating gap, one bushing, a lighter mechanism; asmall tank 0f: insulating matefial instead of a large steel tank and 'only a small percenisage of the =o'i1 iormerly used.

. Anotherobiect is-to provide an improved -circuit interrupteroithe foregoing type with-means 1 (in-minimizing the overall length --of the inter rupt'er and minimizing the width of' thefir-item rupte-r. Preferably; we attain such an' im proved construction by having the movable contact structure telescope within t'he bushing in the fully open "circuit positiomof the interrupter;

hno't'her'ohject is "to provideaspeed contact mechanism fora circuit" interrupter of the foregoing type;

"Further objects and advantages will readily become appanent upon a rea'ding -of" the following specification taken in conjunction with drawings, in which:

Figure l is an elevational 'view of acircuit in terrupter embodying' our invention;

Fig. 'Z isa fragmentary enlarged 'vertical sec- T the contact and are extinguishingti'onal View structure df the circuit interrupter shown I in Fig"; 1, "the'parts-be'ing shown in the'closed circuit position;

Fig, 3 is'anenlarged eleyeitionahview-partly in section of theimproved -operatingmechanism of our invention, taken -substantiaily alongjthe line III- 11T "oi Fig; 4, thapartsbeing'shownin the closed circuityposition;

a sectionalyiew taken along the line IV'TV 'OfFi g. '3, and" *the conventional dead tank cylindrical insulating :tube 1-8.

Fig. '5 showsa modified type of con-tactoperating'arr-angement.

Referring to the drawings and more particular-ly to Fig. 1 thereof, the reference numeral 1 generally designates support means at ground potential; The-support means comprises suitable struetural steel framework including vertica-lly extending supports? braced by diagonally eXtendi-ngangle members 8 Abased is-provided uponwhich the suppcrtingf-ramework stands.

The circuit interrupter 5of" our invention is supportedb-y the grounded 'support means i, and has an upper stationaryline terminal "6 and a lower line terminal-means 1; The external circuit is connected through the interrupter by the wires-'8; 9;

Referringmore par ticularly to Fig; 2, it *will be observed" that the circuit interrupter of our "impreved construction com-prises an enclosure 1!! formed by a casing d lef'porcelain or a material of Weatherproof construction. The porcelain casing H seats upon a-gasket ll-supported by a ring shaped member [3, in turn supp'orted by a metallic cylinder H. "-Dhe cylinder 14 is suppor tedby Lthe circumferentialportion of a pluralityoispring washers l-, the inner ends of whioh are forced by bolts fli toward a casting member H;

The casting member M is supported by a The upper end ofthe :tube I 8 is supported by a ring-shaped member if-Q secured' -ey bolts :20 to a metallic ring 2 i The metallic ring 24 is secured to asupport member 2 2' by weld ing or'the like, the upper end of the support member 22 inturn beingsecured to=one or .more channel members 23 forming a part -oi the support means -I. A platen is secured by suitable means,- not shown, to the support member 22 and supports a high voltage busli ing generally: designated by the "reference numeral 2-5; pre'ferablyof the condenser"type intermediate the ends thereof; More specifically,

the elate 2 41sattachedby bolts 24ato ametallic support-member 2%, the latter-supporting an insulatingcylinder 25a through which extends av conducting tube :or elongated conductor 25!). Thus the conducting means 28 "for "the circuit interrupter-incfluding the tube-25b extends through the support means l by-means of "the high voltage condenser bushing 25.

An arc extinguishing unit or-an extinguishing means, generally designated by the reference mimeralfii isdisposed adjacent oneend of the conducting means' 28 extending through the bushing 25; and terminal-means 21 =for the interrupter are positioned adjacent the opposite side of the arc extinguishing unit 26 from the conducting means 28.

The longitudinally extending conducting means 28 comprises contact means including a movable rod-shaped contact 29 having a rack 30 formed on its right side, as viewed in Fig. 2, and biased downwardly toward the closed position by a compression spring I4 disposed in a conducting tube 15. A gear 3I meshes with the rack 36 to cause the actuation of the same. Secured to the gear 3I is a pinion 32, the gear and pinion being supported on a pin 33 which passes through two opposed vertically extending support plates 34, 35 carried on the end of the bushing 25, as more clearly shown in Fig. 4.

Meshing with the pinion 32 is a gear segment 36 secured to an arm 31, the latter being pivoted on a bolt 38 and having an integrally formed sleeve portion 69. The sleeve portion 39 has an operating arm 49 integrally formed therewith which makes pivotal connection at M to an operating rod 42 formed of a suitable insulating material. The operating rod 42, it will be noted, extends substantially longitudinally of the conducting means 28 and is actuated by a lever 43 making pivotal connection to the operating rod 42 at 44. A shaft 45 serves to rotate the lever 43 and hence to eifect reciprocating, substantially vertical motion, of the operating rod 42. Preferably, a bumper mechanism 46 is provided assuming in this instance the form of a compression spring 41 encircling a rod 48 and seating upon a washer member 49 actuated vertically by a portion 50 of the lever 43.

Surrounding the bushing 25 is a current transformer winding 5| to serve as a measure of the magnitude of the current passing through the interrupter. The winding 5| is connected to suitable measuring equipment which will actuate suitable relays, not shown, in response to overload conditions existing in the circuit connected to the interrupter.

From the foregoing description, it will be apparent that the spring washers I5 place the porcelain casing I I in compression and also place the insulating cylinder [8 in tension. Preferably liquid 52, such as oil, fills the casing to the level indicated by the line 53.

The specific arc extinguishing unit 26 forms no part of our invention and may be of any suitable type. Preferably, however, we employ an arc extinguishing unit of the type described and claimed in U. S. patent application, filed November 11, 1942, Serial No. 465,244, now U. S. Patent 2,406,469, issued August 27, 1946, by Leon R. Ludwig, Winthrop M. Leeds and Benjamin P. Baker and assigned to the assignee of the instant application.

Briefly, such an arc extinguishing unit comprises a pressure-generating contact 54 cooperable with an intermediate contact 55 to form a pressure-generating are, not shown, in a pressure-generating chamber 56. Oil under pressure, as a result of formation of the pressure-generating arc, is forced upwardly through a pair of vertically extending flow passages 51 and inwardly through a plurality of inlet passages 58 to scribes the plate structure and the passage configuration of the arc extinguishing unit 26. A compression spring 6I biases the intermediate contact 55 upwardly. Flexible shunts 62 electrically connect the pressure-generating contact 54 with the lower line terminal I. A compression spring 63 biases the pressure-generating contact 54 upwardly to a limiting position, as defined by the stop 64.

Thus, upon initial upward movement of the movable contact 29, the entire contact structure moves upwardly under the influence of the compression springs 6|, 63 until the stop cap 64 strikes the plate 65. Further upward movement of the intermediate contact 55 and the movable contact 29 creates a pressure-generating are drawn in the pressure-generating chamber 56. Subsequently, the movable contact 29 separates from the intermediate contact 55 when the flange portion 66 of the latter strikes the plate 61 to effect the drawing of an interrupting arc in the interrupting portion 68 of the arc extinguishing unit 26. The oil flow, as previously described, quickly efiects the interruption of the interrupting arc, and the movable contact 29 continues its upward motion to place an isolating gap into the circuit while compressing the biasing means I4.

It will be observed that the gear means 69 which we have provided effects a very rapid upward movement of the movable contact 29 to also rapidly eifect the interposition of an isolating gap into the circuit. It will furthermore be ob-,

served that the movable contact 29 telescopes into the high voltage bushing 25 to thereby minimize the overall length of the breaker.

The are extinguishing unit 26 has been found not only to give excellent interrupting performance but also to result in very little contamination of the oil. Thus, the relatively small volume of oil contained by the insulating casing I8 is suficient for long operational life of the interrupter.

For relatively low voltage service, where such rapid separation of the contact structure is not necessary, the operating rod 42 may be directly connected to the movable contact 29 by a pin connection 10 as more fully shown in Fig. 5. Here again the movable contact 29 telescopes within the bushing 25, a guide support II being clamped to the lower end of the bushing 25 as at 12. With the arrangement as shown in Fig. 5, the movement of the movable contact 29 is more slow than that previously described but is entirely adequate for relatively low voltage service.

From the foregoing description, it will be apparent that we have provided an improved mounting arrangement for a circuit interrupter of the high voltage type in which the expense is considerably reduced by employing a single high voltage bushing. The high voltage bushing 25 is supported intermediate its ends by the grounded supporting framework 24. The shaft 45 may be employed to simultaneously effect the operation of one or more other interrupters, not shown, each of which may be supported by a grounded framework I. Thus, by rotation of the shaft 45 simultaneous operation of all the interrupters, for example controlling the three phases of a transmission line, may be effected.

Byemploying a telescoping construction for the movable contact structure, considerable longitudinal space is saved. Also, the operating mechanism, particularly as shown in Fig. 5, is simple and requires very little lateral space.

Thus, the lateral dimensions of the interrupter need be only slightly larger than the space necessary to house the arc extinguishing unit 26.

From the foregoing, it will be apparent that the interrupter of our invention consists essentially of one condenser bushing, with its current transformers and potential device, a tank consisting of an insulating tube for support and a porcelain weather casing. The insulating tube is a tension member and takes all the shock due to breaker operation, while the porcelain is always resiliently supported and clamped in compression.

The general breaker arrangement not only results in a much cheaper breaker but also one which can be serviced more easily and permits of greater switch yard flexibility. Such an interrupter may be mounted in the towers or on top of the tower or in the roof of a building to save ground space or extendin through the roof thus replacing a wall bushing.

Although we have shown and described specific constructions, it is to be clearly understood that the same were merely for the purpose of illustration and that changes and modifications may readily be made therein by those skilled in the art without departing from the spirit and scope of the appended claims. 7

We claim as our invention:

1. In a circuit interrupter, supporting means at ground potential, a casing a substantial portion of the side walls thereof being of insulating material and providing for a diiference of potential between the ends of the casing, only a single terminal bushing for the interrupter, the terminal bushing including an elongated conductor having insulation disposed thereabout, the terminal bushing being supported intermediate the ends thereof by the grounded supporting means, the terminal bushing projecting into one end of the casing and having the interior end thereof terminating adjacent the mid-portion of the casing, a stationary line terminal disposed at the external end of the terminal bushing, a substantially stationary contact and line terminal means for the interrupter both disposed adjacent and at the potential of the other end of the casing, a movable contact disposed within the casing and movable during the opening operation toward the interior end of the terminal bushing, and actuating means for the movable contact carried by and at the potential of the grounded supportin means.

2. In a circuit interrupter, supporting means at ground potential, a casing a substantial portion of the side walls thereof being of insulating material and providing for a difference of potential between the ends of the casing, only a single terminal bushing for the interrupter, the terminal bushing including an elongated conductor having insulation disposed thereabout, the terminal bushing being supported intermediate the ends thereof by the grounded supporting means, the terminal bushing projecting into one end of the casing and having the interior end thereof terminating adjacent the mid-portion of the casing, a stationary line terminal disposed at the external end of the terminal bushing, a substantially stationary contact and line terminal means for the interrupter both disposed adjacent and at the potential of the other end of the casing, a movable contact telescopically related to the terminal bushing and telescoping into the terminal bushing during the opening operation, means electrically interconnecting the movable contact with the elongated conductor, and actuating means for the movable contact carried by and at the potential of the grounded supporting means.

3. In a circuit interrupter, supporting means at ground potential, a casing a substantial portion of the side walls thereof being of insulating material and providing for a difference of potential between the ends of the casing, only a single terminal bushing for the interrupter, the terminal bushing including an elongated conductor having insulation disposed thereabout, the terminal bushing being supported intermediate the ends thereof by the grounded supporting means, the terminal bushing projecting into one end of the casing and having the interior end thereof terminating adjacent the mid-portion of the casing, a stationary line terminal disposed at the external end of the terminal bushing, a substantially stationary contact and line terminal means for the interrupter both disposed adjacent and at the potential of the other end of the casing, a movable contact disposed within the casing and movable during the opening operation toward the interior end of the terminal bushing, means electrically interconnecting the movable contact with the elongated conductor, actuating means for the movable contact carried by and at the potential of the grounded supporting means, and an insulating operating rod disposed within the casing extending substantially longitudinally of and external to the terminal bushing and mechanically interconnecting the actuating means at ground potential and the movable contact.

LEON R. LUDWIG. BENJAMIN P. BAKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 19,588 Baum May 28, 1935 Re. 21,848 Balachowsky July 1, 1941 945,671 Ball Jan. 4, 1910 1,021,746 Badeau Mar. 26, 1912 1,045,288 Hewlett Nov. 26, 1912 1,991,879 Baum Feb. 19, 1935 2,163,559 MacNeill June 20, 1939 2,221,720 Prince Nov. 12, 1940 2,261,008 Van Sickle et al. Oct. 28, 1941 2,352,048 Wallace June 20, 1944 2,406,469 Ludwig et al. Aug. 27, 1946 FOREIGN PATENTS Number Country Date 18,765 Great Britain Aug. 1902 289,769 Germany Jan. 19, 1916 514,704 Great Britain Nov. 15, 1939 

